Tempering-bath.



- Patentd Aug. l2, |902. J. E. LAWRENCE. I TEMPER'ING BATH.

(Application led June 29, 19C1`.)

v /N vENTb/ .fammi/Mime ATTORNEYS No Model.)

W/T/VESSES JAMES EDWARD LAWRENCE, OE WEST SHEFFORD, CANADA, ASSIGNOR OF ONE-HALF TO VICTOR MARCI-IESSAULT, OF WEST SHEFFORD, CANADA.

TEMPERlNGmBATl-l.

SPECIFICATION forming part of Letters Patent No. 706,966, dated August 12, 1902. Application filed J'une 29,1901. Serial No. 66,509. (No model.) i

The object of the invention istoprovide a new and improved bath designed for hardening steel or other metallic'articles, especially such as dies, tools, andthe like,'and which require a hard face and a softer back.

The invention consists,essentially,rof su-f perimposed liquids, of which oneiscapable of lloatingly supportingthe article to be hardened.

Reference is to be had to the accompanying" drawing, forming a part of Vthis specification,

in which the ligure is a sectional side elevation of the improvement.V Y

As shown in the drawing, the superimposed liquids A and B, preferably mercury and oil, are contained in the vessel C, set'in another vessel D, containing a coolingliquid E. The

heated article F to be hardened is placed downward into the bath,as shown, and sincel the specific gravity of the mercury is greater? than that of the article the article will float upon the mercury, sinking only a short distance into the mercury, so that the face portion of the article is subjected to the action of the mercury and the upper or back portion is submerged in the oil and is hence subjected to the action thereof. The article is left immersed in the bath until it is cool. The action of the mercury on the article F causes the face thereof to be hardened to a very high degree, while the oil leaves the back of the article less hard.

It is evident from the foregoing that a fixed degree of hardness is given to one portion of the article and a different degree of hardness is given to the remaining portion without re quiring any attention on the part of the operator. Thus by allowing the article to float itis automatically hardened to the desired degree,

By the use of suitable tools or other devices the article F may be forced downward far- 5o same and then withdraw into the oil to slowly 5 5 finish cooling it.

By employing a bath formed of two liquids 'one of which is of greater speciiic gravity than uthe articleto behardened the article is rendered self-adjusting as to its position rela- 6o tive to the hardening liquids employed, thereby facilitating theoperation andalso producing a more even hardness of the surfaces of the article. `By forming the bath of oil and mix or freezein ordinary Vcold weather.

Havingthus described -my invention, I

claimas new and'desire to secure by Lett-ers Patent-- A --l. A hardening-bath, comprising a metallic =liquid,and a superimposed liquid of less specific gravity than" the metallic liquid, as set forth. Y

2.: A hardening-bath, comprising a metallic liquid and oil superimposed thereon, as set forth.

3. A hardening-bath, comprising mercury, and a superimposed liquid of less specific gravity than the mercury, as set forth.

4. The herein-described hardening-bath, consisting of oil superimposed on mercury, as set forth.

5. The herein-described hardening-bath,

mercury the two liquids, owing to the great dierence in specific gravity, are not liable to comprising a vessel containing oil, superimposed on mercury, and a second vessel in which the first-named vessel is set, the second vessel containing a cooling liquid, as set forth.

In testimony whereof I have signed. my name to this specification in the presence of two subscribing witnesses.

JAMES EDWARD LAWRENCE. Witnesses:

IsAAc NELsoN, I-I. A. LAWRENCE. 

